They are a distributor for many parts.
Not all are imported. The AR part I'm recommending is american.
Leapers, Inc. - Hunting/Shooting, Sporting Goods and Security Gear
The part so, far gets acceptably good reviews.
Amazon.com: Customer Reviews: UTG Billet Mil Spec Buffer Tube Kit Heavy Duty!!
I agree on preferring different COMPLETE rifles based on the "criteria you stated". Not a fan of Bushmaster for ownership myself, in spite of... I'm sure you know a lot about a slew of parts. But I'm talking about the one you say is a non-recommendable part.
1.Two Friends running it. Rock solid thus far.
2. Reviews... Very good thus far.
While i'm sure you have lots of good experience to share and can probably "teach me" a few things... Your analysis of this "particular UTG part" is unfounded. I will probably end up ordering one myself? Don't need it now but if i come across another cheap stripped lower. I'm buying it fror 3 lowers.
Lowers will be the most important part...
I have a UTG scope mount for an AK, its rock solid and holds zero on my Burris xts-135, I shoot 100-200yrd groups on AK that breaks AK stereotypes. My friends have the UTG buffer on their rifle builds and you have a UTG rifle case. 3 good UTG parts.